Pultrusion is a process designed to combine various materials together into a particular shape. The resulting materials are called composites because they mix different materials for increased strength. For example, pultrusion can be used to combine fiberglass and polyester. The process is called pultrusion, because the materials are pulled through a heated mold that shapes them as they go and hardens the materials into a composited single unit. This technique is used to create a wide variety of objects that are needed in fields as varied as construction and manufacturing.
The pultrusion factory process generally involves a large number of spools of different materials coming from different directions towards a single point, which is the heated mold. The materials are generally pulled from different directions because this can help make the final product stronger. The actual process used for pultrusion can vary depending on the materials that are being composited, but it may involve changes in heat while the materials are inside the mold and points in the process where materials are drenched in certain resins. Many of the resins used are made so that they permanently harden after reaching a certain heat, and this is the reason for the careful temperature control inside the mold.
The method of pultrusion can be used to create almost any shape unless the size makes that shape too unstable with the material being created. The heated mold is technically called a die, and it can be thought of as something similar to a cookie cutter in the sense that it serves the same purpose. It generally needs to create exactly the same shape every time something is pulled through it. The final result generally needs to be reliably the same size and shape, to the point where it can be used in building or any other precision application.
A man named Brant Goldsworthy invented the pultrusion process, and he was a major figure in the invention and development of composite material technology. He came up with the idea of combining various materials together to make stronger plastics while working for an aircraft company that was supplying items for the US Army during the second World War. His creations were so successful the he eventually decided to open his own company, where he made several advancements in the field of composites and created certain plastics that were generally stronger than anything previously seen.